Fair wind for founders: Helmholtz to fund six innovative spin-offs Faster bone loss detection using marine chemistry, equipping cargo bikes with high-performance fuel cells, or simplifying the energy efficiency measurement of buildings – these are three of the six new business ideas selected for the Helmholtz Enterprise funding program. These spin-off projects now have up to 260,000 euros at their disposal for one year. 亥姆霍兹联合会的企业创办基金新选出六个商业创意，并提供单项最高额度26万欧元的资助 Spin-off companies from research are an important way to apply new technologies and findings for public benefit. This is why Helmholtz supports entrepreneurs in the field of science with a number of funding instruments, including the Helmholtz Enterprise program. Since 2005, 176 spin-offs have emerged from the Helmholtz Centers. Approximately half of them were funded by Helmholtz Enterprise. New, promising spin-offs are now ready to launch. Six spin-off projects were included in the program during the current round of calls. Over a period of twelve months, each of the founders receive up to 260,000 euros in funding and go through a number of support programs to turn their business idea into a reality. “We use Helmholtz Enterprise to support brilliant scientists with their business ideas, says Otmar D. Wiestler, President of Helmholtz. Their new companies are the result of years of excellent research at our Centers. Their new products and processes have high potential for innovation. For this reason, they play an important role in bringing technological progress into our daily lives. I wish them much success!” Half of the Helmholtz Enterprise funding comes from the Helmholtz President’s Initiative and Networking Fund, the other half is provided by the Helmholtz Center where the basic technology of the business idea was developed. The six projects currently being funded are: Improved treatment for cancer patients (Theraselect) 改善癌症患者治疗效果 Helmholtz Zentrum München – German Research Center for Environmental Health (HMGU) The Theraselect project aims to create new diagnostic and pharmacological tests to improve treatment for cancer patients. The basis for the spin-off from the Department of Analytical Pathology at the Helmholtz Zentrum München is specially developed methods in mass spectrometry imaging that make thousands of molecules visible in tissue samples. In addition to the cell structure, this makes it possible to see which molecules are present at which location. This can help drug studies to differentiate between active ingredients and their metabolic products in order to verify the success of a treatment. The method also allows specific biomarker profiles to be collected from clinical tissue samples. Based on the results, doctors would be able to make personalized treatment decisions in the future. The locally resolved detection of previously undetectable, tumor-inducing molecules could set new standards in cancer diagnostics. Contact: Dr. Achim Buck Phone: +49 89 3187 4133 Email: achim.buck@helmholtz-muenchen.de Helmholtz Zentrum München – German Research Center for Environmental Health (HMGU) 2. Fuel Cell Power Pack gives cargo bicycles more power (FCPP) German Aerospace Center (DLR), Stuttgart 提供货运自行车动力的燃料电池堆 The German Aerospace Center (DLR) has developed an innovative fuel cell module called the Fuel Cell Power Pack (FCPP), which makes cargo bikes fit for everyday use. It can be refueled in a matter of seconds and performs reliably even at low temperatures. It allows a greater range and twice the service life at similar costs to fully battery-powered systems. It can also be integrated into existing bicycle concepts. The application focus is on what is known as the last mile, meaning the distance between the distribution center and the customer. This is becoming increasingly important due to the rise in e-commerce. The DLR spin-off provides technology and an innovative logistics concept that is faster and more flexible than cars or vans, while also being emission-free and quiet. Contact: Dr. Mathias Schulze Phone: +49 711 6862 456 Email: Mathias.Schulze@dlr.de German Aerospace Center (DLR), Institute of Engineering Thermodynamics, Stuttgart Dr. Christian Rudolph Phone: +49 30 67055 249 Email: Christian.Rudolph@dlr.de 3. Storing valuable muscle stem cells (MyoPax) 珍贵肌肉干细胞的存储 Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC) Rare muscular dystrophies destroy tissue stem cells as well as muscle. This eliminates any chance for those affected to recover through stem cell-based treatments. Intensive research on these treatments is currently underway. MyoPax is the first biobank for muscle tissue at drug level that is expected to enable patients to benefit from these treatments in the future. The founding team from the Experimental and Clinical Research Center (ECRC), a joint facility of the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC) and Charité – Universitauml;tsmedizin Berlin, is working on regenerative treatments for muscle loss to cure more than 50hereditary, previously incurable muscular diseases. They use a patented procedure to extract primary muscle stem cells from routine biopsies. The researchers can then repair genetic defects in these stem cells, multiply them as muscle cells, and regenerate tissue. The MyoPax biobank will store the processed tissue samples for patients until the procedure has been completely developed and officially approved. It is currently undergoing preclinical testing. Contact: Dr. Verena Schouml;wel Phone: +49 30 450 540002 Email: verena.schoewel@mdc-berlin.de Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC) 4. Early detection of bone loss (Osteolabs) 骨丢失的早期诊断 GEOMAR Helmholtz Center for Ocean Research Kiel Osteoporosis or bone loss is a widespread disease that many older women suffer from. The consequences range from broken bones to complete loss of mobility. In the OSTEOLABS project, a research team from the GEOMAR Helmholtz Centre for Ocean Research Kiel and physicians from University Hospital Schleswig-Holstein are developing a non-invasive biomarker based on a marine chemistry analysis method for calcium isotopes that only requires urine or blood for the examination. The biomarker is expected to be able to detect bone loss much earlier than traditional methods and, in the case of an illness, to measure the therapeutic success, thus ensuring a personalized treatment strategy and optimized medication. The goal of the spin-off is to offer the test as a medical device and osteoporosis screening service. OSTEOLABS has already received funding of 1.8 million euros from a validation project of the Helmholtz Association. Contact: Prof. Dr. Anton Eisenhauer Phone: +49 0431 600 2282 Email: aeisenhauer@geomar.de Helmholtz Centre for Ocean Research Kiel 5. Simulation methods for lightweight construction (Simutence) Karlsruhe Institute of Technology (KIT) 轻量化生产的模拟方法 Fiber-reinforced plastics offer excellent mechanical properties such as high material rigidity and, simultaneously, very low weight. This means they offer enormous potential for lightweight construction in vehicle structures. However, currently available software cannot accurately simulate and design the load-bearing capacity of the corresponding components or the manufacturability of production processes. The result of this is a high degree of uncertainty and high costs to develop and use fiber-reinforced plastics. Researchers at the Institute of Automotive Engineering at Karlsruhe Institute of Technology (KIT) have now significantly improved corresponding simulation methods. Through the start-up Simutence, they are offering new processes for the virtual product development of fiber-reinforced plastics as services and as additional modules for commercially available software. Based on process and structure simulations, it is possible to reliably design fiber-reinforced plastics within a virtual process chain and optimize the associated manufacturing processes and components. Contact: Benedikt Fengler Phone: +49 0721 608-45375 Email: benedikt.fengler@kit.edu Karlsruhe Institute of Technology (KIT), Institute of Vehicle System Technology, Institute of Lightweight Construction Technology 6. Rapid energy analysis of buildings and apartments (neofizient) German Aerospace Center (DLR), Cologne and Jülich 建筑与公寓的快速能源分析 About half of the approximately 40 million apartments in Germany will have to be renovated over the next 20 years. Because of energy saving regulations and the large saving potential offered by new materials and technologies, building energy consulting will be required to plan the renovations. These consultations are time consuming and expensive since experts have to perform complex, on-site measurements. The procedure and the documentation are not standardized and are not comparable due to varying standards of quality. It is currently impossible to get a simple assessment of the energetic condition without on-site analysis by an expert. The neofizient spin-off from the Institute for Solar Research at the German Aerospace Center (DLR) offers fast, inexpensive, and standardized preparation of energy building models. The measurement using a newly developed infrared (IR) interior scanner is so simple that it can be performed by anyone. The interior scanner is based on an optical 360° camera system that combines visual and IR data. These data are used to create a 2.5dimensional spatial model that displays energetic information such as the U-value (heat transfer coefficient), thermal bridges, and humidity. Contact: Silvan Siegrist Phone: +49 2203 601 4195 Email: Silvan.Siegrist@dlr.de Dr. Arne Tiddens Phone: +49 2203 601 4174 Email: Arne.Tiddens@dlr.de The Helmholtz Association contributes to solving great, pressing questions facing society, science, and business with top scientific performances in six research fields: Energy; Earth and Environment; Health; Key Technologies; Matter; and Aeronautics, Space, and Transport. With 39,000 employees at 18 Research Centers and an annual budget of over 4.5 billion euros, the Helmholtz Association is Germany's largest science organization. Its work follows the tradition of the great natural scientist Hermann von Helmholtz (1821-1894). Media contact: Dr Martin Kamprath Program Manager Transfer and Innovation Tel.: +49 30 206329-77 martin.kamprath@helmholtz.de Annette Doerfel Press Officer Phone: +49 030 206 329-38 annette.doerfel@helmholtz.de Communication and External Affairs Berlin Office Anna-Louisa-Karsch-Str. 2 10178 Berlin Germany
Fair wind for founders: Helmholtz to fund six innovative spin-offs Faster bone loss detection using marine chemistry, equipping cargo bikes with high-performance fuel cells, or simplifying the energy efficiency measurement of buildings – these are three of the six new business ideas selected for the Helmholtz Enterprise funding program. These spin-off projects now have up to 260,000 euros at their disposal for one year. 亥姆霍兹联合会的企业创办基金新选出六个商业创意，并提供单项最高额度26万欧元的资助 Spin-off companies from research are an important way to apply new technologies and findings for public benefit. This is why Helmholtz supports entrepreneurs in the field of science with a number of funding instruments, including the Helmholtz Enterprise program. Since 2005, 176 spin-offs have emerged from the Helmholtz Centers. Approximately half of them were funded by Helmholtz Enterprise. New, promising spin-offs are now ready to launch. Six spin-off projects were included in the program during the current round of calls. Over a period of twelve months, each of the founders receive up to 260,000 euros in funding and go through a number of support programs to turn their business idea into a reality. “We use Helmholtz Enterprise to support brilliant scientists with their business ideas, says Otmar D. Wiestler, President of Helmholtz. Their new companies are the result of years of excellent research at our Centers. Their new products and processes have high potential for innovation. For this reason, they play an important role in bringing technological progress into our daily lives. I wish them much success!” Half of the Helmholtz Enterprise funding comes from the Helmholtz President’s Initiative and Networking Fund, the other half is provided by the Helmholtz Center where the basic technology of the business idea was developed. The six projects currently being funded are: Improved treatment for cancer patients (Theraselect) 改善癌症患者治疗效果
地幔深部 Fe 的自旋态转换以及富 Fe 硅酸盐熔体 下地幔底部核幔边界之上可能存在着高密度的熔体，这些熔体由于特别富集Fe而比周围地幔物质密度更大，从而可以在这样的极端环境下保持重力稳定。Fe在下地幔中的分配行为伴随着下地幔中Fe的自旋态的转换，即从高自旋态向低自旋态转换，这种行为在下地幔矿物钙钛矿和铁方镁石中已经被广泛观测到。如果这种高低度的富Fe熔体可以在下地幔底部核幔边界之上稳定存在，那么就可能在地球形成演化过程中产生厚达1000km的高密度熔体层，这对于地球内部物质的分异演化以及现在下地幔底部超低速带(ULVZs )的解释具有重要的揭示意义。这一成果发表在最新一期2011年5月12日《Nature》杂志上，正是由发现后钙钛矿(post-perovskite)的日本科学家Kei Hirose小组利用激光加热金刚石压砧(LHDAC)完成了相关实验。（译者注） Nature原文链接： http://www.nature.com/nature/journal/v473/n7346/full/nature09940.html Supplementary Information (5.1M)： http://www.nature.com/nature/journal/v473/n7346/extref/nature09940-s1.pdf PDF文档下载： 2011-Nature- Spin crossover and iron-rich silicate melt in the Earth’s deep mantle .pdf 熔体与同成分的硅酸盐固相相比具有更大的体积。但是在高压条件下这一差距将会缩小，并且现在普遍推测具有这样一种可能性，那就是，在地球内部（以及其他类地天体）高压条件下大量富集重元素 Fe的熔体比固相密度更大 (1,2)。这些致密硅酸盐熔体在下地幔底部的出现，将会对其物理化学演化产生重要影响，并可以提供一个统一模型来解释核幔边界区所观测到的一些特征 (3)。最近的理论计算 (4)以及在浅部地幔条件下对 (Mg,Fe)SiO 3 钙钛矿和熔体之间 Fe的分配关系的估计(5-7)表明， 在地球最深部地幔高压条件下熔体比固相密度更大 ，这与冲击波实验分析结果一致(8)。本文我们将 Fe分配关系测量扩大到整个地幔压力范围，发现 在大于 ~76 GPa压力时有一个明显突变，导致 Fe在熔体中的强烈富集 。随后对 (Mg 0.95 Fe 0.05 )SiO 3 玻璃的 X光发射光谱分析显示在大约 70 GPa时有一个自旋态突降 (spin collapse)，这表明所观测到的 Fe分配关系的变化可以用硅酸盐熔体中 Fe的自旋态转换 (从高自旋态到低自旋态 )来解释。这些结果意味着 在下地幔 ~1800 km深度条件下 (Mg,Fe)SiO 3 液相比共存的固相密度更大 。在地球刚形成早期，由增生作用 (accretion)和内部分异 (internal differentiation)所释放的热量可以在固体地幔下面形成一个厚达 1000 km的致密熔体层。我们也推测 (Mg,Fe)SiO 3 钙钛矿在深部地幔条件下处于液相线状态，致密岩浆的分异结晶作用 (fractional crystallization)会逐渐向富 Fe贫 Si成分演化，这与地震学上对核幔边界区结构的推测是一致的 。 我们的熔融实验是在激光加热金刚石压砧 (laser-heated diamond-anvil cell, DAC) 上进行的，样品总体成分为 (Mg 0.89 ,Fe 0.11 ) 2 SiO 4 ，压力条件为 20-159 GPa 。为了避免出现异常热扩散，加热时间控制到比较短 ( 见补充材料 ) ，但是这也使我们难于测量熔融温度。不过实验中温度的上下限可以分别由 Mg 2 SiO 4 液相线温度以及天然橄榄岩的固相线温度来给出 ( 见 Methods 以及补充材料图 1) 。从 DAC 回收的样品用高分辨率场发射电子探针显微分析仪 (FE-EPMA) 进行了分析。回收样品显示同心结构，这反映了加热过程中的温度分布 (Fig.1) ，与常见的多顶砧实验 (5-7) 中所观测的结构类似。我们在样品中间温度最高部分总是观测到一个斑点 (pocket) ，它具有非化学计量比的成分，我们将其看作是淬火局部熔体 (quenched partial melt) 。该淬火熔体的 ( Mg+Fe)/Si 摩尔比随压力增加而增大 ，从 36 GPa 时的 1.50 到 159 GPa 时的 2.56( 补充材料图 2) 。该熔体斑点被一个单相固体层 ( 铁方镁石或者钙钛矿，视压力条件不同 ) 所包围，我们认为这是在降温过程中最先结晶的相 ( 液相线相 )(5,7) 。 Figure 1: Backscattered electron images and X-ray maps for Si, Mg and Fe for samples recovered from high-pressure melting experiments. a , At 32 GPa, when ferropericlase (Fp) is the liquidus phase; b , at 76 GPa, when perovskite (Pv) is the crystalline phase in contact with the quenched melt pocket; and c , at 159 GPa in the stability field of post-perovskite (PPv). Quenched melt was found at the centre of the sample, where the temperature was highest. Metallic iron was observed at the edge of the laser-heated area in all samples, where a strong temperature gradient existed 28 . It was also found in the melt pocket, but only above 36 GPa where the liquidus phase was perovskite or post-perovskite. Arrows in a represent the directions of the laser beams for heating. See Supplementary Information for the valence state of iron in the partial melt. 在本研究中，在 20-36 GPa 时液相线相是铁方镁石 (ferropericlase) ，在更高压力下则逐渐被钙钛矿所取代 ( 在 36 GPa 时两者同时都与熔体池接触 ) (Fig.1) 。考虑到样品中 Mg/Si 比值的差异 (7) ，这与橄榄岩成分物质的观测结果 (5) 一致，其中在 31 GPa 以上条件下液相线相从铁方镁石变成钙钛矿。尽管实验中并没有做物相鉴定，但是在 143-159 GPa 条件下的实验中应该会形成后钙钛矿 (post-perovskite) 。在 36 GPa 时液相线相从铁方镁石向钙钛矿的转变表明，共熔 (eutectic) 熔体成分在高压条件下更加富 Mg 。这与熔体中 (Mg+Fe)/Si 摩尔比随压力增加而增大的现象是一致的 ( 补充材料图 2) ，尽管熔体成分与熔融程度也是相关的。 Figure 2: Change in Fe-Mg distribution coefficient and calculated density profiles. a , K D = (Fe Pv /Mg Pv )/(Fe melt /Mg melt ) between perovskite (blue circles) or post-perovskite (red squares) and melt; the values drop sharply at pressures above 76 GPa, probably due to the effect of the spin crossover of iron in silicate melt (see Fig. 3 ). Previous experimental datum obtained at 25 GPa using a multi-anvil apparatus is shown by a grey circle 6 . Error bars were estimated from uncertainties (1 σ ) in both solid and liquid compositions. b , Density of the (Mg,Fe)SiO 3 liquid coexisting with (Mg 0.92 Fe 0.08 )SiO 3 perovskite calculated for 4,000 K using the newly obtained Fe-Mg partitioning data. Data for (Mg 0.86 Fe 0.14 ) O ferropericlase 29 , Ca-perovskite 30 and PREM 19 are also shown for comparison. Liq, liquid; Fp, ferro-periclase; CaPv, calcium silicate perovskite; MgPv, magnesium silicate perovskite. 钙钛矿 / 后钙钛矿和熔体之间的 Fe-Mg 分配系数 K D = ( / )/( / ) ，在 36-159 GPa 压力范围内均得到测定 (Fig.2a) ，其中钙钛矿 / 后钙钛矿为液相线相。尽管淬火熔体斑点含有多价态的 Fe(Fig.1b,c) ，但是我们将高温下所有的 Fe 均看作为 Fe 2+ ( 见补充材料 ) 。 K D 值在 73 GPa 以下几乎保持恒定不变 ( 大约 0.22-0.29) 。这与前人在含 Al 橄榄岩总体成分 (5-7) 中的测量结果 (~0.4) 相比要低一些，但是与不含 Al 的橄榄岩物质 (6) 在 25 GPa 条件下所获得的 K D =0.304 ± 0.035 非常一致。在含 Al 体系中高 K D 值应该是由于钙钛矿中的高 Fe 3+ 含量引起的 ( 见 ref.9) 。另一方面， K D 在 76 GPa 时会突降到 0.07±0.02(Fig.2a) 。随后一直到 159 GPa 则几乎保持恒定在 0.06-0.08 。 Figure 3: Evolution of X-ray emission spectra of (Mg 0.95 Fe 0.05 )SiO 3 glass with increasing pressure. Measurements were conducted at 300 K. All spectra are normalized to transmitted intensity, and shifted so that the weighted average of main (Kβ) plus satellite (Kβ′) emission lines is set to 7,058 eV. The satellite peak decreased slightly at 59 GPa and completely disappeared at 77 GPa, indicating the spin crossover of iron. 为了研究 76 GPa 以上条件下 Fe 在熔体中强烈富集的原因，我们在 300 K 、 8-85 GPa 条件下对 (Mg 0.95 Fe 0.05 )SiO 3 玻璃进行了 X 光发射光谱分析 (Fig.3) 。在低压下， Fe 的 Kβ ′ 峰 (satellite peak) 在 7045 eV 非常明显，指示玻璃样品中的高自旋态的 Fe 2+ 。这一峰在 59 GPa 时会减弱，而在 77 GPa 时会消失。这表明了二价 Fe 中的自旋态转换。因为玻璃是液态的一个很好的类似物，这样一个 Fe 的高自旋向低自旋态的转换也可以在相似压力条件下的熔体中产生，因此为熔体中所观测到的 Fe 富集的突变而提供了一种解释 ( 见 refs. 10, 11) 。确实在我们的玻璃样品中所观测到的自旋态转换的压力范围与 K D 急剧变化的压力 (Fig.2a) 是相符的。我们的熔体比 (Mg 0.95 Fe 0.05 )SiO 3 玻璃具有更高的 Mg/Si 比值以及 FeO 含量；但是 Mg 2 SiO 4 流体中所计算的平均 Mg-O 和 Si-O 配位数 (12) 与下地幔压力条件下 MgSiO 3 流体中的值 (13) 非常相近。因此，与 Mg/Fe-O 配位相关的自旋态转换压力不会伴随着熔体中 Mg/Si 比值从 1 变化到 2 而产生明显偏移。理论研究 (14,15) 表明，当 Fe 浓度很低时 ( 低于 ~20%) ， Fe 含量并不会改变自旋态转换的压力范围，因为 Fe-Fe 相互作用是可以忽略的。多顶砧实验 (16) 结果表明，在自旋态转换开始时，钙钛矿和铁方镁石之间 Fe 的分配会产生急剧变化，这与我们的观测具有可比性。 Figure 4: Evolution and crystallization of dense melts in the deep mantle. a , During Earth's early history, any melts that form below ~1,800 km depth sink and accumulate at the base of the mantle, while any crystals that form owing to cooling of this dense magma will rise upward into the solid mantle. b , Fe-poor perovskite crystallization leaves a residual liquid enriched in FeO and depleted in SiO 2 , and crystals forming from this evolved liquid may become dense enough to form thermo-chemical piles at the base of the solid mantle. c , The final stage of crystallization involves a composition close to wüstite, leaving behind a very dense thin layer that is consistent with the seismic properties inferred inside ULVZs. White arrows indicate schematic flow patterns in the convecting solid mantle. Fe 分配关系的巨大变化表明在 1800 km 深度以下熔体会变得更加致密。我们计算了与 (Mg 0.92 Fe 0.08 )SiO 3 钙钛矿 ( 地幔岩下地幔的代表成分 (16,17)) 达到平衡的 (Mg,Fe)SiO 3 流体， 在 4000K 条件下随压力变化的密度 (Fig.2b) 。为简化起见，在 75 GPa 以下我们使用 K D =0.25 ，在更高压力下我们使用 K D =0.07 。 MgSiO 3 流体的摩尔体积根据最近的第一性原理计算结果 (4) 获得， Fe 的作用对于流体相和固相 ( 钙钛矿 ) 假设是相同的 (4,18) 。但是 (Mg,Fe)SiO 3 熔体在 75 GPa 以下时与任何典型下地幔矿物相比都是具有浮力的，而在更高压条件下则会突然变得密度更大。在地幔底部与初始参考地球模型 (PREM)(19) 的差距达到 8% 。本实验中熔体的 Mg/Si 比值比 MgSiO 3 高 ( 补充材料图 2) 。根据前人的冲击波压缩实验 (8) ，这种高 (Mg+Fe)/Si 熔体可能比上面所讨论的 (Mg,Fe)SiO 3 熔体密度更大，从而表明熔体和固体之间的密度转换可能发生在比 1800 km 更浅的深度。尽管有关熔体在地幔底部的详细情况并不是十分清楚，但是我们的结果为下地幔中可能存在的厚达 1000 km 的稳定熔体层提供了约束条件 (Fig.4) 。 Labresse 等 (3) 已经提出了一个模型，在地球形成不久所产生的致密熔体，可以构成一个相当大的“基底岩浆海” (basal magma ocean, BMO) ，它在几十亿年中缓慢结晶，其速率由上覆固体地幔中相对缓慢的固相对流所控制。我们的实验结果为固体地幔下高达 1000 km 的 BMO 的重力稳定性提供了一个新的物理证据，并且上面所推测的最大的可能厚度与 BMO 假说在广范围来说是一致的。例如，一个 1000 km 厚的 BMO 可以构成地幔 1/4 的质量；分异结晶作用以及冷却过程中残余流体中热量所产生的不相容元素 ( 如 U,Th) 的隔离，可以解释“丢失”的球粒陨石成分，这些物质可能被隔离在地幔中的某个储库中 (20) 。我们的实验结果也可以帮助我们对 BMO 的性质以及其化学演化过程随时间的变化做进一步的推测。 正如上文所提到的，我们的结果说明， (Mg,Fe)SiO 3 钙钛矿是从熔体中最先结晶出来的相，并具有较广的 (Mg+Fe)/Si 比值；对于核幔边界条件下 (Mg+Fe)/Si≈2.5 的贫 Si 熔体来说依然是这样的 ( 补充材料 Fig.2) 。这充分说明， BMO 冷却过程主要是以钙钛矿的结晶作用为特点，其他的相如 (Mg,Fe)O 镁方铁矿 (magnesiowustite) 只在相对较晚的时期结晶。另外， BMO 中形成的钙钛矿晶体将会相对亏损 Fe ，并漂浮到 1800 km 深度以下的岩浆区的顶部 (Fig.4) ，因为其 Fe/Mg 分配 K D 值较低。由此，我们可以推断残余岩浆将会向富 FeO 贫 SiO 2 成分演化 ( 即接近于方铁矿的成分 ) ，随时间密度变得更大，而且可能会保留相当量的不相容挥发性物质。 经过如上文所讨论的分异结晶演化，同样也可以影响从 BMO 所形成的堆积岩的成分。尤其是当从越来越富 Fe 的岩浆中结晶出来时，堆积岩会随时间变得更加富 Fe 密度更大。这些高密度堆积岩最终将可以保持稳定而不会被地幔对流所带走，并在地幔底部集中形成热化学堆积 (Fig.4) 。这些致密固体物质的堆积，大约比平均地幔密度高 2-3% 并构成 ~2% 的总体地幔体积，可以解释太平洋和非洲地区 (21) 下面地幔底部两个巨大的低剪切波速省 (low-sheaer-wave velocity provinces, LLSVPs) ；这些高密度物质的富 Fe 成分与这些异常 (22) 大小是一致的。 BMO 中更高程度的结晶作用也可以在核幔边界之上的薄层中产生一些高密度残余体补丁，这将可以解释超低速带 (ultralow-velocity zones, ULVZs)(23) 的出现以及地震波速特征。这些物质在地质历史时期里可以保持在或接近固相线，因为参与流体将会隔离不相容物质，相应地也会降低熔融温度。那么后期富方铁矿的堆积岩从富 Fe 贫 Si 熔体中结晶出来将会产生一个高密度固相层，即使没有熔体 (24) ，其地震波特征同样与来自 ULVZ 的地震反射仍然是一致的。 BMO 模型以及我们实验所推测的成分演化过程，与两种可能性都是相容的。另外一种可能，有助于解释为什么不同地区的 ULVZs 并不总是显示相同的地震特征 (25) ，那就是在一些 ULVZs 中间隙中的熔体已经完全抽干，留下一个强烈富集方铁矿的不含熔体的固相岩石。在另外一些 ULVZs 中，由于周围地幔中存在不同的动力学条件，上覆地幔流粘度耦合作用所产生的这些糊状残余体的连续扰动，将会阻止岩石的固结和熔体的分离 (26) 。不含熔体富集方铁矿的 ULVZ 和固有的糊状的 ULVZ 之间，我们所预计观测到的主要区别就是，剪切波速的降低幅度，在糊状 ULVZs 中降低幅度更大 (27) 。 参考文献： Stolper, E., Walker, D., Hager, B. 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标签: spin
